This invention relates to vessel loading apparatus. In particular, this invention relates to a vessel loading apparatus specifically designed to be utilized in combination with portions of existing vessel loading structures known as "pocket docks" to permit utilization of such pocket docks to load vessels of such increased length, beam and hatch height as are presently being used and are proposed to be used for purposes of transporting bulk materials.
"POCKETS DOCKS" ARE DOCKS WHICH HAVE LONG BEEN IN USE ON THE Great Lakes for purposes of loading bulk materials. They have been recognized as the most efficient means of loading bulk materials such as coal and iron ore into bulk carriers for water transportation to destinations such as power plants and steel plants.
The first of such docks were built in the early Twentieth Century. However, even today, they are considered to be a fast and efficient means to load vessels of older classes as used on the Great Lakes, which vessels have a beam of 75 feet or less.
Pockets docks are presently in use at approximately 12 facilities and operate in the handling of millions of tons of bulk materials per year.
A typical pocket dock of known design consists of multiple double storage bins or pockets spaced at 12 feet intervals along a finger pier of such length as to accommodate one or more vessels on either side of the pier. The pockets (i.e. the bins) receive material by gravity from bottom dump railroad cars positioned by locomotives over the pocket tops. During the vessel loading operation, material is discharged by gravity from the pocket into the vessel through gates and loading chutes or spouts located at the bottom of each pocket. Each spout is hinged at the bottom of the pocket to permit it to be raised to a non-operating position clear of the dock line or lowered into the hatch opening of the vessel being loaded at such an angle as to permit material to flow freely, by gravity, from the pocket into the cargo hold.
Most of the existent pocket docks have sufficient storage capacity of material in the pockets to permit loading the older class of vessel without filling the pockets during the loading operation.
Notwithstanding the demonstrated efficiency of the pocket docks, they are not structurally capable of handling the new, larger vessels presently being utilized or proposed to be utilized for carrying bulk material. Thus, with the arrival of such new super bulk carrier vessels, other means of loading such vessels economically have been under consideration.
The magnitude of the problem is best reflected with consideration for the size of the vessels being served.
The new vessel class has a beam of 105 feet and future vessels are contemplated with beams of up to 130 feet. In addition to the increased width, these vessels are of a deeper draft and obviously have cargo carrying capacities which are greatly in excess of the capacities of vessels previously loaded at the pocket docks and for which the pocket docks were designed. The increased beams, drafts and carrying capacities of the new classes of vessels preclude efficient loading from the facilities provided at the existing pocket docks. Loading spouts used with such pocket docks operate on a gravity principle and therefore must be lowered to an angle sufficiently steep to permit adequate flow of material being loaded. Such a pitch requirement renders them incapable of providing adequate reach away from the dock face to load larger beam vessels. Further, the vessels which have a greater draft when loaded have a higher free board when unloaded and as such the increased free board presented by the newer classes of vessels may be such as to preclude a satisfactory angle of inclination on the loading spout to permit a flow of material. This, of course, incapacitates the dock.
It has also been recognized that the capacity of the new classes of vessels is normally greater than the combined capacity of the pockets in the existing docks. In order to overcome this difficulty and still use the presently existing facilities, it has been known to load one side of a large vessel first on one side of the pocket dock and thereafter to move the vessel to another dock to load the other side. Clearly this is time consuming and an inefficient and expensive operation.
Prior to the present invention, it was generally accepted in the industry that the only way to accommodate new vessels at existing pocket dock facilities was to demolish the existing pocket docks and replace them with travelling shiploaders. This approach was undesirable because the existing pocket docks are in excellent condition, their structure is more than adequate to support loads presented by the volumes and masses of the new bulk material and by reason of their excellent structural condition, their demolition would be an extremely expensive project. The present invention rejected the idea that demolition of the existing docks was required and resulted from a desire by the inventors to utilize, to the extent possible, the existing pocket dock facilities while at the same time providing a capability for handling the bulk materials required to load the newly proposed classes of vessels in an efficient period of time.
It is acknowledged that an approach to the utilization of the existing pocket dock facilities has been sought. Various schemes were proposed to achieve this end, all without success. Included in these schemes were: a travelling device mounted on the water side of the pocket section of the dock to receive material from the bottom of the pocket and thereafter convey it into the vessel; a portable vehicle equipped with a conveyor to ride on the deck of the vessel and transfer material from the loading spouts of the pocket dock to the vessel hatch openings or other ancillary conveyor arrangements; and portable or fixed conveyor devices installed on the vessel to transfer material deposited by the loading spouts to the vessel hold. None of these proved either structurally or financially feasible.